Tuesday, June 10, 2014

New paper shows IPCC underestimates global cooling from man-made aerosols/clouds by factor of 27 times

According to a new paper published in Science, the globalcooling effect of clouds nucleated by man-made aerosols since the beginning of the industrial revolution is approximately 15 watts per square meter, which is about 27 times more cooling effect than the mean estimate published in the 2014 IPCC AR5 Report:

Radiative forcing estimates from the 2014 IPCC AR5 Report show "cloud adjustments due to aerosols" since 1750 are a mean value of 0.55 watts per meter squared [+/-0.8] with level of confidence "low."

In the absence of aerosols, there can be no cloud nucleation. Scientists on an icebreaker in the Arctic demonstrated this in a video of a cup of hot tea that does not fume despite the below-zero temperatures. Then, someone flicks on a lighter and water vapor from the tea grabs aerosol particles emitted by the lighter (due to inefficient combustion) and a tiny storm appears, above the teacup.Researchers penetrate one of the darkest mysteries of climate change -- clouds

There is little wind. These latitudes, between 30 and 35 degrees away from the equator, are so calm that Spanish sailors in the 17th century could not move their heavily laden ships, or so the legend goes. So, the sailors dumped their cargo -- horses -- into the subtropical ocean and heaved on. But they left the place with a name: Horse Latitudes.

These windless tracts have yielded a new hypothesis relevant to climate science: Few clouds may have populated our skies before the Industrial Revolution, and pollutants spewed by factories since then may have vastly increased the cloudiness of our atmosphere. The results were published yesterday in the journal Science.The finding cuts to the heart of uncertainty contained in climate models today. Most scientists agree that humans are releasing massive quantities of carbon dioxide into the atmosphere and causing global temperatures to rise. But they disagree on the rate of warming. A doubling of CO2 concentrations could warm the planet by between 2 and 4.5 degrees Celsius, according to the Intergovernmental Panel on Climate Change (IPCC).[actually, the latest IPCC report revised the lower bounds to 1.5C, not 2C]

Part of the uncertainty is due to clouds. They come in various shapes and types, as most people know -- puffy popcorns (cumulus); loose brush strokes of mostly ice (cirrus); towering, dark monsters of thunderstorms (cumulonimbus) and many others.

Clouds can either reflect the sun's incoming rays back into space, cooling the Earth. Or they can act as a sheath and trap heat close to the Earth's surface, warming the planet. Often, they do a little of both. And they do it incredibly well. Clouds have the ability to heat the planet much more than CO2, depending on the type of cloud, its geography and its altitude. And to make things more complicated, cloud particles can have various sizes, shapes and physical traits. Translating these into predictions about the overall effect of clouds on the climate can be quite difficult.

Replacing a simplistic view

Today's climate models do include clouds, but some types are better represented than others.

“Unfortunately, the climate system is very sensitive to little changes in clouds,” said Andreas Muhlbauer, research scientist at the Joint Institute for the Study of the Atmosphere and Ocean at the University of Washington. He was not involved in the Science study. “So being off by just a bit in a climate model can have a significant impact on the ability to predict.”

Lumpy clouds (marine stratocumulus clouds) off the west coast of continents are well represented in climate models. The Science study unravels another cloud type -- the cumulus -- which some scientists say are poorly represented in climate models.

These clouds are so complicated that it can take a couple of days to explain them, said Ilan Koren, a planetary scientist at the Weizmann Institute of Science in Israel and lead author of the study, reached while en route to a Rolling Stones concert.

"I'm sorry, but there are no simple answers here," he said.

Koren and his colleague, Orit Altaratz, also a scientist at Weizmann, base their findings on a well-accepted theory -- that clouds grow rapidly in the presence of microscopic particles called aerosols. In the past, aerosols used to be mainly microscopic salt particles from the ocean, debris from volcanoes, organic material or bits of soil carried by the wind. Since the Industrial Revolution, black carbon and soot from our cars, factories and cook stoves constitute most of the cloud-forming aerosols.

Aerosols are key in whipping up a cloud, a process that begins with the sun. As the sun's rays hit the ocean, water evaporates into the gas phase. Water vapor attaches itself to aerosol particles floating in the air and condenses into a seed of water and dust that blooms into a full-fledged cloud that climbs up the sky.

In the absence of aerosols, there can be no cloud. Scientists on an icebreaker in the Arctic demonstrated this in a video of a cup of hot tea that does not fume despite the below-zero temperatures. Then, someone flicks on a lighter and water vapor from the tea grabs aerosol particles emitted by the lighter (inefficient combustion) and a tiny storm appears, above the teacup.

Adding just a little bit of pollution goes a long way toward cloud formation in a very pristine environment, said Muhlbauer of the University of Washington.

Computer models must wait for better data

"Ultimately, it [aerosols] affects the amount of clouds that are out there, and also the properties of the clouds -- the area, for example, they cover over the globe. And all that affects the radiation that can actually hit the [Earth's] surface," Muhlbauer said.

To demonstrate the aerosol effect, Koren and his colleagues observed clouds forming in the Horse Latitudes of the Southern Hemisphere. This region of the global oceans has little wind, which means pollutants are not easily carried over from continents. A few clouds may exist, but not too many given the aerosol-starved nature of the region.

The scientists used data from four different satellites to observe the clouds, the aerosol content, temperature, meteorology and rainfall over 92 days in the winter of 2007. They found that the skies became more overcast as the aerosol levels in the air increased naturally. And the effect did not cease; there was no point of saturation beyond which aerosols stopped affecting the clouds.

As the cloud cover doubled, they reflected more incoming solar rays back to space. Thus, the clouds had a cooling effect.

Koren and Altaratz hypothesized that the last time the skies were this clean of aerosols -- other than in the Horse Latitudes, that is -- was before the Industrial Revolution. The skies then must have been much less cloudy than today, Koren said.

An implication of this theory is that as these cumulus clouds became more widespread at the very beginning the Industrial Revolution could have cooled the Earth. Including these clouds in climate models could alter results significantly.But there's no way to know for sure. No one maintained records of aerosol levels in preindustrial times, and for now, Koran's suggestion is mere speculation.

Muhlbauer said this was an "interesting" scenario but cautioned that the findings are extremely preliminary. Adding cumulus clouds into climate models is a "long way off," he said.

5 comments:

"According to a new paper published in Science, the global cooling effect of clouds nucleated by man-made aerosols since the beginning of the industrial revolution is approximately 15 watts per square meter, which is about 27 times more cooling effect than the mean estimate published in the 2014 IPCC AR5 Report:"

Sounds to me like they are going to use this 'science' to say that the CO2 induced warming would be a lot worse if it wasn't for these pesky aerosols.

1. Would require GHG forcing to be ridiculously high ~12W/m2 higher than IPCC currently estimates.2. The entire radiative forcing concept is wrong. The greenhouse effect is due to gravity, atmospheric mass, pressure as established in several other posts. The troposphere is in radiative/convective equilibrium set by solar insolation & atmospheric mass/gravity/lapse rate, not greenhouse gas concentrations.

All this discussion about aerosols reminds me of (dare I say it) "chemtrails". Hypernucleation of atmosphere drives drought and drives the GHG, water vapor to cause less rain and increased surface temps. We saw it happen over the Pacific to force drought in California to out pressure on food and water resources as if insiders are wagering on commodity futures.

It does remind me as well, TSN. They will use this data to promote all the heavy metals such as barium oxide and aluminum oxide from the chemtrails where to save us from global warming death. It was for our own good!